• Add "!" to your regular finder methods to raise an ActiveRecord::RecordNotFound error if an empty array is returned
• Works for find! as well as dynamic find_[all_]by_*! methods

Example:

  def reset_password
    @user = User.find_by_login!(params[:id])
    @user.password = "changeme"
    @user.save
    flash[:notice] = "#{@user.login}'s password was reset!"
  rescue ActiveRecord::RecordNotFound
    flash[:error] = "No such user."
  ensure
    redirect_to :action => 'index'
  end